Airtel Prepaid
Security amount - non refund

I had a postpaid connection for a couple of months with airtel, wherin i was to deposit a security amount for international calls. I have switched over to prepaid now and have been requesting for the refund of the security amount for over a year now but they just dont seem to entertain the request. everytime i call the customercare, which generally takes an hr to get to the customer care, iam told to call airtel postpaid n if i call airtel postpaid iam told to call prepaid! completely annoying!